[Solved?] Did I miss this? Can't set Mute Toggle Shortcut?

You have not missed anything, there is no shortcut to mute a track, however, I found a solution you might like,if you don't know about this already, when you're on a track just use the right and left arrow keys to make the little white corners appear on the mute button and press enter, (you only have to do this once as long as you are muting and unmuting things) the track can be muted, and unmuted the same way, and at that point you can use the up and down arrows to go to different tracks and the mute button will still be available to just press enter to mute or unmute. Same goes for naming tracks, solo, etc. 
 
for me, MCU pro has that "sliced bread" effect.
 
 

I have mapped the following:

backslash ( \ )  to "Set all selected tracks to Muted Status"
Forward slash ( / ) to  "Solo all selected tracks"

The text between the quotes above is exactly as the respective texts appear in the function list.

promidi
I have mapped the following:

backslash ( \ )  to "Set all selected tracks to Muted Status"
Forward slash ( / ) to  "Solo all selected tracks"

The text between the quotes above is exactly as the respective texts appear in the function list.

I don't think that's the same thing, if you have to select a track you might as well mute it with the mouse like he said

frankjcc
I don't know, They did this to me with one of my most used shortcuts, but I found a way to get it back, I just went to an older version of Sonar where I had things the way I liked them, and I exported the keybindings and guess what, they worked, so chances are they still work, it's just no way of assigning them. this short of mine still works till this day,  
 
If I select multiple tracks I can just press alt O and then I can arrow down to set all outputs to a particular buss, I like this much better than the new way.

Interesting idea, but too many other shortcuts would get changed